8 containers and 7 pails can hold 76.6 litres of water.
1 container and 1 pail can hold 9.9 litres of water.

1. How many litres of water can 1 container hold?
2. How many litres of water can 1 pail hold?
3. How many litres of water can 6 pails hold?
4. How many litres of water can 9 pails and 8 containers?

(a)
8 containers + 7 pails = 76.6 --- (1)
1 container + 1 pail = 9.9 --- (2)

(2) x 7
1 container + 1 pail = 9.9
7 containers + 7 pails = 9.9 x 7
7 containers + 7 pails = 69.3 --- (3)

(1) - (3)
(8 containers + 7 pails) - (7 containers + 7 pails) = 76.6 - 69.3
8 containers + 7 pails - 7 containers - 7 pails = 7.3
8 containers - 7 containers + 7 pails - 7 pails = 7.3

1 container = 7.3

Volume of 1 container = 7.3 ℓ

(b)
Substitute 1 container = 7.3 into (2).
1 container + 1 pail = 9.9
7.3 + 1 pail = 9.9

1 pail = 9.9 - 7.3 = 2.6

Volume of 1 pail = 2.6 ℓ

(c)
Volume of 6 pails
= 6 x 2.6
= 15.6 ℓ

(d)
Volume of 9 pails and 8 containers
= 9 x 2.6 + 8 x 7.3
= 23.4 + 58.4
= 81.8 ℓ

Answer(s): (a) 7.3 ℓ; (b) 2.6 ℓ; (c) 15.6 ℓ; (d) 81.8 ℓ